High density cotton population in late sowing improves productivity and tolerance to cotton leaf curl virus under semi-arid subtropical conditions

Abstract

Cotton leaf curl virus (CLCuV) is a menace to cotton productivity in Africa and Asia, especially in Pakistan. Early cotton planting is one of the options for CLCuV management, but due to late harvesting of wheat crop in cotton-wheat cropping system, early planting is not feasible. To address this problem, a two-year experiment was conducted at Department of Plant Breeding and Genetics, The Islamia University of Bahawalpur, Pakistan. The experiment includes a commercially grown and approved cotton genotype IUB-13 grown at two spacings i.e. normal spacing (30 cm plant-to-plant distance) and high density population (15 cm plant-to-plant distance). In both cases, row-to-row distance was kept constant i.e. 75 cm. From the experiment, data were collected for CLCuV infestation, seed cotton yield (SCY), number of bolls per unit area (NB), boll weight (BW), above ground fresh biomass (AGFB), harvest index (HI), ginning out-turn (GOT) and fibre quality traits e.g. fibre length (FL) and fibre fineness (FF). Significant reduction in above mentioned traits was observed mainly attributed to higher CLCuV infestation in late sown cotton (30th May, 2018 and 2019). It was clearly evident from the results that yield losses due to CLCuV were effectively compensated in late sowing with high plant densities (reducing the plant spacing) due to improvement in the AGFB and HI.